While ORP (Oxidation-Reduction Potential) isn't commonly measured by most reef tank owners, those who do generally do so to control their ozone generator or to keep a pulse on their tank. If your goal is to control your ozone generator, you can follow these guidelines: Option: Control Type Select 'ORP Control' Option: Fallback Select 'Off' so the generator will turn off should the energy bar lose connection with the Apex base unit. Option: Probe Name Select 'ORP' Option: High Value You'll want to keep this below 450, we set ours to 380. Option: Low Value You'll want to keep this above 300, we set ours to 350. Option: On When Set this to 'low'. This program will turn your ozone generator on if the ORP falls below the 'Low Value', and will remain on until it hits your 'High Value. At that point it will turn off until it again hits your 'Low Value' and the cycle continues. If your goal is to monitor ORP simply to keep a heartbeat on your tank, you may want to set-up both an email and sound alarm with a statement similar to 'if ORP (greater than) 450 Then ON" or "if ORP (less than) 200 then ON". If you have any questions or suggestions for you fellow reefers on how you use ORP checkout the comments area below. Don't miss our next episode, hit that subscribe button! :) Check out the entire Apex line: http://brs.li/neptuneapex Watch the whole playlist: https://www.youtube.com/playlist?list=PLBaMLrfToJyz8091y-PoECoUo5QfMGg1S Connect with us on Facebook: http://www.facebook.com/BulkReefSupply Check out our pics on Instagram: http://instagram.com/bulkreefsupply